[llvm] r344084 - [FPEnv] PatternMatcher support for checking FNEG ignoring signed zeros
Cameron McInally via llvm-commits
llvm-commits at lists.llvm.org
Tue Oct 9 14:48:00 PDT 2018
Author: mcinally
Date: Tue Oct 9 14:48:00 2018
New Revision: 344084
URL: http://llvm.org/viewvc/llvm-project?rev=344084&view=rev
Log:
[FPEnv] PatternMatcher support for checking FNEG ignoring signed zeros
https://reviews.llvm.org/D52934
Modified:
llvm/trunk/include/llvm/IR/PatternMatch.h
llvm/trunk/lib/Analysis/InstructionSimplify.cpp
llvm/trunk/test/Transforms/InstSimplify/fast-math.ll
Modified: llvm/trunk/include/llvm/IR/PatternMatch.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/PatternMatch.h?rev=344084&r1=344083&r2=344084&view=diff
==============================================================================
--- llvm/trunk/include/llvm/IR/PatternMatch.h (original)
+++ llvm/trunk/include/llvm/IR/PatternMatch.h Tue Oct 9 14:48:00 2018
@@ -666,6 +666,13 @@ m_FNeg(const RHS &X) {
return m_FSub(m_NegZeroFP(), X);
}
+/// Match 'fneg X' as 'fsub +-0.0, X'.
+template <typename RHS>
+inline BinaryOp_match<cstfp_pred_ty<is_any_zero_fp>, RHS, Instruction::FSub>
+m_FNegNSZ(const RHS &X) {
+ return m_FSub(m_AnyZeroFP(), X);
+}
+
template <typename LHS, typename RHS>
inline BinaryOp_match<LHS, RHS, Instruction::Mul> m_Mul(const LHS &L,
const RHS &R) {
Modified: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=344084&r1=344083&r2=344084&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/InstructionSimplify.cpp (original)
+++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp Tue Oct 9 14:48:00 2018
@@ -4508,10 +4508,8 @@ static Value *SimplifyFDivInst(Value *Op
// -X / X -> -1.0 and
// X / -X -> -1.0 are legal when NaNs are ignored.
// We can ignore signed zeros because +-0.0/+-0.0 is NaN and ignored.
- if ((BinaryOperator::isFNeg(Op0, /*IgnoreZeroSign=*/true) &&
- BinaryOperator::getFNegArgument(Op0) == Op1) ||
- (BinaryOperator::isFNeg(Op1, /*IgnoreZeroSign=*/true) &&
- BinaryOperator::getFNegArgument(Op1) == Op0))
+ if (match(Op0, m_FNegNSZ(m_Specific(Op1))) ||
+ match(Op1, m_FNegNSZ(m_Specific(Op0))))
return ConstantFP::get(Op0->getType(), -1.0);
}
Modified: llvm/trunk/test/Transforms/InstSimplify/fast-math.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/fast-math.ll?rev=344084&r1=344083&r2=344084&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/fast-math.ll (original)
+++ llvm/trunk/test/Transforms/InstSimplify/fast-math.ll Tue Oct 9 14:48:00 2018
@@ -401,9 +401,7 @@ define float @fdiv_neg_swapped2(float %f
define <2 x float> @fdiv_neg_vec_undef_elt(<2 x float> %f) {
; CHECK-LABEL: @fdiv_neg_vec_undef_elt(
-; CHECK-NEXT: [[NEG:%.*]] = fsub <2 x float> <float 0.000000e+00, float undef>, [[F:%.*]]
-; CHECK-NEXT: [[DIV:%.*]] = fdiv nnan <2 x float> [[F]], [[NEG]]
-; CHECK-NEXT: ret <2 x float> [[DIV]]
+; CHECK-NEXT: ret <2 x float> <float -1.000000e+00, float -1.000000e+00>
;
%neg = fsub <2 x float> <float 0.0, float undef>, %f
%div = fdiv nnan <2 x float> %f, %neg
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